Embedded Modem Development, Fiscal Cash Registers And Silver Tax System In One Machine

At most in the last few years, the embed equipments enters the lately applied realm constantly, embed system development also along with develop continuously. In the product of the development by Hisense Intelligent Commercial Equipment Company, everywhere it is thus clear that the application of the embed equipments. Among them, in tax control accept the payment machine net report the tax system with the tax administration backstage and silver Carry on the communication work with the bank backstage in the tax integral whole machine of, is a embed modem. The development of the embed modem, then textual and main contents.The research and development of embed modem is composed by three parts:the prophase analyse, the middle design, the anaphase testing. The prophase analyzes accomplishes the choice of modem chips and the confirm of project. The middle design accomplishes the design of schematic and PCB. The anaphase testing accomplishes the test of the product which is designed in the middle design part. The most part is the middle design part. The middle design part is the longest and the weightily part in this project. The schematic is the precondition in this part. The schematic perfect, the whole project can go on wheels. Thenceforth PCB's design requests strictness. The strictness can reduce the anaphase change and shorten the time limit for project.This paper will gather up three parts' content by combining the facing difficult problems and the resolution for the problems. Especially, I will particular describe the advanced content which is beneficial to developing.In this develop process, a little bit main and difficult problem that I resolve have:1. Under the condition of guaranteeing that the function is outstanding, the technique province that uses the forerunner went to the in common use transformer of past, reducing the size and the physical' volume of the equipments. 2. For replying various abrupt circumstance, guarantee the normal work of the built-in modem and link the safety of the equipments with it. At prevent from the thunder influence, keep circuit electric voltage, electric current from unsteady influence aspect, do a detailed but overall design.The technique realization of above these problems have:Make use of the economical and in common use transformer of the American Silicon Laboratories third generation DAA( the direct access arrangement) technique realization and reduce the equipments size and physical volumes; Adopt the big capacity electric capacity and press the electric resistance and PTCs to prevent from the influence of the thunder, keep circuit electric voltage, electric current from unsteady influence;Use the Protel 99 SE design four layer PCB circuit boards that stability is strong.